This invention relates to photoelectric sensors and in particular to through beam photoelectric sensors. More particularly, the invention relates to a low cost photoelectric sensor assembly for a through beam photoelectric sensor which may readily be repaired in the field.
The use of sensors to monitor the presence or absence of an object, its position, or some other condition of the object in manufacturing and handling apparatus is steadily increasing, due largely to the availability of computers, microcomputers and the like which can quickly respond to the sensed conditions and make appropriate changes in the process. A piece of manufacturing or material handling apparatus may contain numerous sensors. Photoelectric sensing is a popular form of sensing for many applications. However, the cost of photoelectric sensors is a deterrent to using this form of sensor in the growing quantities conceivable for such manufacturing and material handling apparatus. Moreover, since most sensing applications are in manufacturing production lines, and since it is undesirable to shut down such production lines for repair of any element thereof, repair of most photoelectric sensors presently available comprises replacement of the sensor on the site.